white blood cells prepared by dr. hamad alassaf [email protected] 2015
TRANSCRIPT
Leukocytes / White Blood Cells
Granulocytes (65%)- neutrophils, eosinophils, basophils
- formed in bone marrow
Monocytes (5%)- tissue macrophages
- formed in bone marrow
Lymphocytes (30%)
- formed in lymph tissue
- life span: hours to years
Leukocytes Classification
• Granulocytes Non- Granulocytes– Neutrophils - Monocytes– Eosinophils - Lymphocytes– Basophils
• Polymorphonuclear Mononuclear– Neutrophils - Monocytes– Eosinophils - Lymphocytes– Basophils
• Phagocytes Non-phagocytes– Neutrophils, monocytes - Lymphocytes– Macrophages, eosinophils - Basophils
Phagocytic Cells
1- Polymorphonuclear Neutrophils- non-dividing, short-lived (6 hours to a few days)
- dominant number in bloodstream
2- Monocytes/Macrophages- long-lived cells (months)
- do not circulate
- present in tissue, particularly in lungs, spleen, liver, lymph nodes
- tissue macrophage system
Actions of Phagocytic Cells
1. Margination
2. Diapedesis
3. Ameboid Motion
4. Chemotaxis
5. Phagocytosis
Actions of Phagocytic Cells
1. Binding
2. Engulfment
3. Phagosome formationAcidificationproteolysis
4. Lysosome fusion
5 Membrane disruption
6-Antigenpresentation
MHC II
Phagocytosis
Cell-mediated Response to Inflammation
1. Tissue macrophages:
- already present in tissue
2. Neutrophil invasion:
- margination, diapedesis, chemotaxis
- stimulation of bone marrow to release stored leukocytes, 4-5 hours
3. Macrophage proliferation:
- invasion by circulating monocytes (several hours to increase size)
4. Stimulation of granulocyte and monocyte production:
- growth factors produced by tissue macrophages (TNF, IL-1, Cell stimulating factor)
Increased Transmigration
Blood vessel
Tissue Site of inflammation
Blood vessel
TissueTransmigration
Circulating and marginated pools
NORMAL PRODUCTION INFECTION
Marrowpool
Bone BoneIncreased circulationIncreased margination
Production IncreasedProduction
Decreasedmarrow pool
Granulocytes
• EOSINOPHILS:
- ~ 2% of total white blood cells
- active against parasites, skin diseases, chronic infections
- phagocytic and immunomodulatory, decrease inflammation
- life span 5 days
• BASOPHILS:
~ 0.5% of total white blood cells
- basophils similar to mast cells
- release primarily histamine, some bradykinin
- release due to binding of IgE
- Life span a few hours to a few days
Important terms
• Leukopenia : decrease in the number of white blood cells. example: bone marrow suppression
• Leukocytosis : increase in the number of white blood cells. example : bacterial infections
• Leukemia : (cancerous) uncontrolled production of white blood cells
Neutropenia
Neutropenia: decreased number of neutrophils due to:
Decreased production Increased neutrophil destruction (chronic infections)
Agranulocytosis: severe neutropenia due to:
production failure due to irradiation exposure to chemicals drugs
Immunity
It is a special defense mechanism which is mobilized when the body is invaded by a foreign organism.
Immunity
Innate = (present since birth)
- ability to resist damaging organisms and toxins - skin, gastric acids, tissue neutrophils and macrophages, complement
Acquired = (developed by exposure to specific invading agents).
- humoral ----> circulating antibodies - cellular ----> activated cells
Sequence
- Dormant lymphocytes
- Invasion of body by foreign antigen
- Phagocytosis by macrophages
- Presentation of antigen to lymphocytes
Antigen
An antigen: is a substance that can induce an
immune response when introduced into an
immunocompetent host and that can react with the
antibody produced from that response.
Bone MarrowStem cell
Pre-BCell
Pre-TCell T-Cell
T8-supressor
T4-helper
B-Cell Plasma Cell
IgG IgA IgM IgD IgE
LymphocytesT- and B-Cells
Thymus
Liver and Bone
marrow
T-cells
Cytotoxic Cellskill infected cells
Helper Cells ( CD-4 cells)activate macrophages and B-cells
Suppressor Cellsregulate activity